Multi-protocol over ATM (MPOA) represents an important development in the communications industry in that it permits the internetworking of local area networks (LANs) over an ATM backplane. This internetworking leads to the efficient delivery of a range of multimedia services such as video, voice, image and data.
Heretofore, MPOA internetworking architectures have not been capable of servicing more than one user network. Current internetworking devices within the network architecture provide one or more functions related to forwarding data packets through a network. The primary keys used to control internetworking forwarding functions are network addresses. Within a particular network these network address keys must be unique for the correct operation of the forwarding functions. In many internetworking systems, in particular those based on the internet protocol, the correct operation of the forwarding functions requires the additional constraint that these network address keys be organized in an ordered hierarchy of partial address prefixes where the unique set of keys used to control the internetworking forwarding function at different points within the network are different. One such system is disclosed in EP-A-0797 331 published Sep. 24, 1997. The prior art relates to networks involving ATM workstations and switches connectable to multiple legacy LAN workstations. For example, in WO 96/04729 published Feb. 15, 1996, there is disclosed a system including one or more interconnected emulated networks to which legacy LAN workstations are connected. Traffic within an emulated network is switched while traffic between emulated networks is routed. In current systems, a router and bridge combination sometimes known as a ridge provides the address keys in order to forward the data packets to the proper destination.